1. Field of the Invention
The present invention relates in general to integrated circuits and in particular, to a system-on-a-chip with circuits and methods for debugging an embedded processor and systems using the same.
2. Description of the Related Art
Handheld personal electronic appliances have become increasingly popular as new technologies have produced affordable devices with a high degree of functionality. One such device is the portable digital audio player, which downloads digital audio data, stores those data in a read-writable memory, and converts those data into audio on user demand. The digital data is downloaded from a network or retrieved from a fixed medium, such as a compact disk, in one of several forms, including the MPEG Layer 3, ACC, and MS Audio protocols. An audio decoder, supported by appropriate firmware, retrieves the encoded data from memory, applies the corresponding decoding algorithm and coverts the decoded data into analog form for driving a headset or other portable speaker system.
The use of systems-on-a-chip in the design and construction of handheld digital music players allows all the requisite functionality to be contained in a compact, relatively inexpensive unit. Notwithstanding, the integration of the major functions of a digital music player into a single chip device is not a trivial task. Not only must the device include the processing power capable of performing digital to audio conversion efficiently, it must also be capable of interfacing with various sources of digitally encoded data, support different user I/O options, such as LCD displays and headphones, and operate in conjunction with sufficiently large on-chip and off-chip memory spaces storing (programming code and data) needed to produce high-quality audio.